Simple logging implemented

Message now stores a copy of the content string
Use .nick() instead of .account() to get the users lowercase name (login name)

logging/loggingmanager.h

@@ -0,0 +1,17 @@
+#ifndef LOGGINGMANAGER_H
+#define LOGGINGMANAGER_H
+
+#include "loggingchannel.h"
+
+#include <memory>
+
+namespace chatterino {
+namespace logging {
+
+void init();
+std::shared_ptr<Channel> get(const QString &channelName);
+
+}  // namespace logging
+}  // namespace chatterino
+
+#endif  // LOGGINGMANAGER_H